I am not a strict Reconstructionist, but yes, I try to keep their festivals. The point? Well, I think everyone has a different reason for keeping the traditions. There are those who are interested in and recreate ancient cultures, those who like mythology, those who work with the gods as symbols and archetypes, and those who believe the gods actually exist. In short, there’s room at the banquet for many different perspectives. And, depending where you live, there might be a good-sized crowd celebrating! You’re welcome to join in, dear Anon - though I recommend you substitute grape juice for wine, until you are of legal drinking age in your jurisdiction.
Anthesteria was one of the four annual Athenian festivals in honor of Dionysus. On the first day, Pithoigia (which was yesterday), dwellings were decorated with flowers. New vessels of wine were opened, and everyone - including children, slaves, and the spirits of the dead - celebrated and made offerings to Dionysus. The second day, Choes (today), was dedicated to drinking and merriment. It was also the day of a solemn ritual in which the basilissa (a ceremonial Queen) was wed to Dionysus. This was a secret ceremony, so no one knows exactly what it entailed, but some scholars believe it was a reenactment of the marriage of Ariadne to Dionysus. On the third day, Chytroi (which is tomorrow), offerings were made to the souls of the dead, who were then bidden to depart.
You can read more about the Reconstructionist celebration of Anthesteria at: http://www.hellenicgods.org/anthaestiria and http://societasviaromana.net/phpBB3/viewtopic.php?f=5&t=1032
Io, Bacchus! Hail,Dionysus!